I found the problem and now OpenGL works perfectly, and guess what it was??...

.....It was Stardocks WindowBlinds.

The program must put some kind of transparent overlay on the desktop which was causing the problem. I got the idea when I noticed that every time I opened Poser there was a split second screen flicker so I unloaded WindowBlinds and ended the wbvista.exe process, restarted and poof the problem was gone. So now Windowblinds is uninstalled untill I can get a hold of support and see if there's some sort of workaround/patch.

Thanks for all the comments and suggestions guys, they're much appreciated :)